(1) Field of the Invention
The invention relates to a lathe with a vertically positioned motor-driven work spindle on whose lower end are positioned workpiece clamps, with an initial compound slide system by means of which the work spindle can move vertically in the Z1 direction and horizontally in the X1 direction, with at least one initial stationary tool holder, and with at least one second tool holder which can execute an advancing action in at least one direction during the machining process, while the advancing movement of the second tool holder is independent of the control of the first compound slide system.
Lathes of this type, which are known, e.g., from DE 34 16 660 C2, have proven their usefulness in many ways. In such tooling machines clamping means are used to mount the workpiece in suspended fashion on a vertical work spindle, which is driven with a motor. A compound slide system is employed to move the work spindle in the vertical direction Z1 and in the horizontal direction X1. In this way the work spindle can be moved between a workpiece transfer point and a work space. At the workpiece transfer point the work spindle takes up the workpiece being machined, or releases a machined workpiece. In the work space the workpiece is lathed by a stationary tool as the work spindle executes the Z1 and X1 advancing actions of the machining process.
DE 196 07 883 A1 describes a lathe with the capability of passing a workpiece between two clamping chucks each belonging to a work spindle and of using a tool to machine in both clamps. Simultaneous machining of the workpieces with two tools is not possible here; when one tool is at work the other is blocked. An exemplary embodiment in DE 196 07 883 A1, FIGS. 14 and 15, shows the addition of a third tool holder so as to permit a workpiece in a defined position to be machined with two tools. One tool is in fixed position, the second can be moved along an axis. Since the second tool only moves along an axis perpendicular to the rotational axis of the workpiece that is being machined, simultaneous machining is not provided—only a rapid changeover from machining with the first tool to machining with the second tool.